Transporte selectivo de nutrientes a través de membranas poliméricas de inclusión basadas en líquidos iónicos

Abstract

In recent years, the use of membranes based on ionic liquids has been applied in a wide range of separation processes. The main objective of this Thesis is to study the transport of nutrients through polymeric inclusion membranes based on the ionic liquid. Specifically, methyltrioctylammonium chloride was used at different concentrations in the liquid membrane. In this way, we intend to broaden the range of applications of membranes based on ionic liquids. For this purpose, a dual chamber device separated by the polymeric ionic liquid membrane was used. The nutrients analyzed were, sodium nitrate, sodium hydrogen phosphate, calcium chloride and magnesium sulphate. Subsequently, the evolution of the nutrient concentration in the reception phase was analyzed for 7 days (168 h) and the permeability values were adjusted to a solubilization-diffusion transport model. The results showed very low permeability values for Calcium Chloride. On the contrary, the permeabilities values for Sodium Hydrogen Phosphate were higher than for calcium chloride. It was also observed that they increased of the ionic liquids immobilized in the membrane involved an increasing of the permeability values. The surface of the membranes was characterized before and after their use in the experiments using scanning electron microscopy coupled with energy dispersive X ray spectroscopy (SEM-EDX). The SEM-EDX analysis showed that the polymeric ionic liquid inclusion membranes were stable in contact with aqueous nutrient solutions. The technology of polymeric inclusion membranes based on ionic liquids could be implemented for effective control of matter transport between the anodic and cathodic compartments of a microbial fuel cell or a microbial fuel cell with heterotrophic denitrification at the anode. Its ionic nature would allow the transport of protons between both chambers, and, on the other hand, the ionic liquid would exercise specific control over the component salts of the anodic and cathodic phases, either avoiding their loss in a specific compartment or allowing the passage of one to another depending on the immobilized ionic liquid. The results obtained in this thesis could also be applied to different fields such as the separation and purification of salt mixtures.